Power hammer



July 9, 1963 c. v. ADAMS 3,096,831

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3,096,831 POWER HAMMER Campbell' V. Adams, Chicago, lll., assigner to Vulcan Iron' Works Inc., Chattanooga, Tenn., a corporation of Illinoisv V 4 FiledlDec. 27, 1960, Ser. No. 78,366 8 Claims; (Cl. 173-127) This invention relates broadly to power hammers and moreparticularly to the type of power hammers known as p ile'hammers, in which a ram is automatically operated by motive iluid supplied to the cylinder to impart motion to the ram. A known -power hammer is described and illustrated in my prior Patent No. 2,004,180, issued June 11,1935.

The power hammer includes a cylinder member and a piston member operatively positioned within the cylinder, :Motive iluid is supplied to the cylinder to automatically operate the piston. A heavy weight or ram is operatively connected to the piston to deliver heavy pile driving iblows against an anvil which in turn tran-smits the blows to the pile. One type of hammer known as the single-acting hammer utilizes the motive uid on the upstroke of the pis-ton to raise the ram and thereafter exhauststhe motive iluid to permit the piston and the ram to lfall by gravity and strike a blow. Another type of hammer known as the double-acting hammer not only utilizes the pressure of' the motive lluid against the piston to raise the ram, but also to accelerate the downstroke of the ram. Moreover, pile hammers may be of either the open type or the sub-aqueous or closed type. 'Ihe open type ofpile driving hammer has exposed working parts. On the other hand, the closed type has the working-parts in a sui-table housing, as illustrated in my abovementioned prior patent. no exposedl working parts are desirable tot the protection they aliord against water, sand and other destructive or corrosive elements particularly when driving piles over water.

Heretoforc it has been known to connect the piston and ram through a piston rod having an enlarged spherical head and tted Within a split bushing, as clearly illustrated in my prior Iaforementioned patent. The bushing is then bolted or pinned to the ram. While this arrangement has proven satisfactory when used with the open type of pile hammers, diiculties have been encountered with this connection in closed hammers. While the cause of the `dilliculty is not fully understood, it is believed to arise in part because of fthe loose par-ts in the closed housing.

It is therefore an object of the present invention to provide an improved pile driving hammer.

Another object of the present invention is to provide an improvedA closed type power hammer.

A further object of the present invention is to provide a pile hammer having an improved connection between the piston and the ram.

A further object ofthe present invention is to provide an improved connection between lthe piston member and ram member `of a closed type pile hammer.

Further objects and advantages of the invention will becomeapparent as the following description proceeds and thefeatures of novelty which lcharacterize the invention will be pointedout with particularity in the claims annexed to and forming a part ofthis speciication.

Brieliy stated, in accordance with the present invention, the piston member of a pile driving hammer is provided with a slot in one end thereof, and a connecting rod member having one end secured'to the ram of the hammer is provided with a complementary tongue at its other end which is received and thereby locked in the slot of the piston. In an illustrated embodiment, the slot is a T- Such closed hammers having United States Patent O ice -slot and the complementary tongue is T-shaped. However, it is to be understood that other slot and tongue conligurations, such as cylindrical or square, may be used. In one embodiment, the connecting rod is :secured 'to the ram by an interference fit between the connecting rod and an aperture in the ram. While the aforedescribed connection is equally applicable to open and closed types of pile hammers, it is particularly advantageous on closed type hammers since, as explained above, the prior connections have not been entirely satisfactory when used on the closed type hammers.

The nature of the invention will be better understood when described in connection' with the accompanying drawing, in which: l

FIG. 1 is a sectional elevational view of a power pile hammer incorporating the present invention;

FIG. 2 is a cross-sectional view of the pile hammer of FIG. l taken along line 2 2 of FIG. 1; and

FIG. 3 is an exploded isometric View of the improved rod and piston connection.

The structure and operation of a power hammer is illustrated fand described in my prior aforementioned patent and need not be fully ydescribed herein. However, briey, the power hammer comprises a suitable housing 1 provided with sheaves 2 which may be arranged upon a cylinder head 3 to receive cable or like flexible members controlling- 'the vertical movement of the hammer. The cylinder head 3 is attached to a cylinder block 4 within the housing 1. A piston member 5 having a main piston 5a in the cylinder- 4 is operatively connected to a ram 6 through a piston or connecting rod 7. The Ilower end 4a of the cylinder is reduced in diameter to provide an auxiliary cylinder chamber 8 receiving an auxiliary piston 5b of piston member 5 which forms a seal at the lower end of the cylinder 4. The usual piston rings 5c may be employed .to assure a tight tit.

For operating the power hammer motive uid is supplied to the cylinder 4. The power hammer disclosed herein is adapted to be operated by any suitable motive fluid such Vas steam or compressed air.

Timed movement of a valve (not shown), more fully described in my prior aforementioned patent, c-ontrols the fluid to the upper cylinder so that during the entire cycle fluid vn'll be supplied at full pressure below the piston, and -will be supplied at the same or full pressure above the piston during Ithe cushioning period of upstroke and accelerating period of the downstroke. As the piston 5 reaches its lowermost position or position of impact, as illustrated by` the solid lines of FIG. 1, theV motive iluid in the cylinder above the piston is exhausted to atmosphere or otherwise. Fluid will again be admitted to the cylinder above the piston appreciably before the end of its upstroke, illustrated in phantom in FIG. 1. The purpose of admitting this uid is to Iallow it to act as a cushion for the accelerating piston. Moreover, the motive fluid thereafter remains in the chamber above the piston during the downstroke so that the energy of this Huid-is superimposed upon the `dead weight of the ram, piston and connecting r'od during the downward or power stroke of the hammer. The housing 1 is provided with a plurality of ram guides 20 which cooperate with vertical slots 21 in the ram 6 to guide the ram for vertical movement in the housing 1. To receive the force of the pile driving blows of the hammer 6, there is provided an anvil 22 which is loosely positioned at the lower end of the hammer through a flexible cable or chain 23 which tie the anvil 22. to the housing 1.

To connect the piston member 5 and connecting rod 7, the piston member S is provided with a slot Sid at its lower end for the reception of the connecting rod 7. The slot 5d is generally T-shaped and comprises generally a neck or narrow outer slot 5e communicating with a wider inner slot 5f of trapezoidal shape, the side walls 5g of which are inclined toward each other away from the narrow slot 5e. The connecting rod 7 has a generally complementary T-shaped tongue 7a including a narrow portion 7b having substantially parallelA sides, and a generally trapezoidal cam portion 7c having sides 7d thereof which are inclined toward each other away from the body of the connecting rod 7. While the tongue 7a is generally complementary to the T-slot 5d, suflicient clearance is provided between the sides of the tongue and the sides o-f the T-slot so that the connecting rod 7 and piston member 5 may tolerate a small amount of misalignment. Misalignment between the connecting rod 7 and piston member 5 in the longitudinal direction of the slot and 'tongue is provided for by relative longitudinal displacement of the tongue 7a with respect to the T- slot 5d.

To secure the connecting rod 7 to the ram 6, the ram 6 is provided with a central aperture 6a of slightly smaller diameter than the cooperating portion of the connecting rod 7. The cooperating portion of the connecting rod 7 comprises a cylindrical section 7e slightly larger than the diameter of the aperture 6a, which is an interference tit with the ram 6; the ram `6 is pressed or shrunk on the section 7e.

In operation, the piston 5, connecting rod 7, and ram 6 are raised vertically upwardly from the position shown in solid lines in FIG. 1 to the position shown in phantom in FIG. 1 due to the pressure exerted by the motive fluid on the underside of piston 5a. Just before the assembly reaches its uppermost position, motive iluid is permitted to enter the yupper portion of the cylinder above piston 5a thereby cushioning the movement of the assembly. This pressure, along with the dead' weight of the assembly, will force the ram 6, connecting rod 7, and piston member 5 to exert a downwardly directed blow on the anvil 22, which, in turn, will transmit the blow to a pile (not shown).

While the hammer disclosed herein is 'designed principally as a power pile driver, it is equally applicable for analogous punposes, as, for example, where a percussive blow is used, suc-h as in rock drilling, riveting maohines, concrete breaking or tamping or the like. Moreover, the present invention has particular applicability to sub-aqueous or closed type of power hammers, since the enclosed type of power hammers have been subjected to particular diculties with the prior known connections, as enumerated above. While the applicant has illustrated and described a single preferred embodiment of his invention, it is understood that it is intended in the appended claims to cover all such modifications as fall within the true spirit and scope of the invention.

What is claimed as new and desired to be secured by Letters Patent of the United States is:

1. A power hammer comprising a cylinder member, a piston member operating in said cylinder member and having a slot in one end thereof, means for supplying motive fluid to said cylinder to operate said piston, a ram, and a connecting rod member having a complementary tongue at one end loosely positioned in said slot providing clearance between the sides of said tongue and said slot to allow for slight misalignment between the piston member and the connecting rod member and having its other end secured to said ram.

2. A power hammer comprising a cylinder member, a piston member operating in said cylinder member and having a T-slot in one end thereof, means for supplying motive iluid to -said cylinder to operate said piston, a ram, and a connecting rod member having a T-shaped tongue at one end loosely positioned in said T-slot providing clearance between the sides of said T-shaped tongue and said T-slot to allow tfor slight misalignment between t-he piston member and the connecting rod member and having its other end secured to said ram.

3. A power hammer as set forth in claim 2 above wherein said ram is provided with a central aperture and said connecting rod contains a cylindrical section at its other end slightly larger in diameter than said aperture and positioned in said aperture in interfering it therewith.

4. A pile driving hammer of the closed type comprising a housing, a fluid cylinder member within said housing, a fluid piston member operatively positioned in said cylinder member and having a T-slot in its lower end, guide means in said housing, a ram vertically reciproc-ally movable on said guide means and provided with a central aperture opening upwardly, a connecting rod having a T-shaped tongue at one end thereof loosely positioned within said T-slot and having a cylindrical section at its other end thereof of slightly greater diameter than said aperture and positioned within said aperture thereby forming a tight intenfering tit with said ram, and means lfor supplying motive iluid to said cylinder to operate said piston so that said ram, connecting rod and piston are effective to produce power blows, and an anvil positioned to receive said blows and transmit said blows to a pile.

5. A pile driving hammer as set forth in claim 4 above wherein said Ihammer is of the double acting type.

6. A pile driving hammer of the closed type comprising a housing, a fluid cylinder member within said housing, a Huid piston member operatively positioned in said cylinder member and having a slot in its lower end, guide means in said housing, a ram vertically reciprocally movable on said guide means and provided with a central aperture opening upwardly, a connecting rod having a complementary tongue at one end thereof loosely positioned within Vsaid slot and having a cylindrical section at its other end thereof of slightly greater diameter lthan said aperture and positioned within said aperture thereby forming a tight interfering tit with said ram, and means for supplying motive fluid to said cylinder 4to operate said piston so that said ram, connecting rod and piston are effective to produce power blows, and an anvil positioned to receive said blows and transmit said blows to a pile.

7. A piston and rod connection for use in a power hammer of the type including a piston member operating in a cylinder member with means lfor supplying motive uid to the cylinder to operate the piston, a ram provided with a central aperture, and a connecting rod member having one end slightly larger in diameter than the aperture and positioned within said aperture in interfering rit therewith, said connection comprising a T-shaped tongue formed at the other end of said connecting rod member and positioned in a T-slot in one end of said piston member.

8. A piston and rod connection as set tforth in claim 7 above wherein clearance exists between the sides of the T-shaped tongue and the T-slot to allow lfor slight misalignment between the piston member and the connecting rod member and wherein said tongue can move longitudinally in said slot to provide for misalignment between said connecting rod member and said piston member in a longitudinal direction.

References Cited in the le of this patent UNITED STATES PATENTS 1,008,026 Gilman et al. Nov. 7, 1911 1,281,196 Norrbom Oct. 8, 1918 1,899,846 Boyd Feb. 28, 1933 1,957,021 Schneider May l, 1934 2,004,180 Adams June ll, 1935 2,436,908 Van Weenen et al. Mar. 2, 1948 2,906,245 McCall Sept. 29, 1959 

1. A POWER HAMMER COMPRISING A CYLINDER MEMBER, A PISTON MEMBER OPERATING IN SAID CYLINDER MEMBER AND HAVING A SLOT IN ONE END THEREOF, MEANS FOR SUPPLYING MOTIVE FLUID TO SAID CYLINDER TO OPERATE SAID PISTON, A RAM, AND A CONNECTING ROD MEMBER HAVING A COMPLEMENTARY TONGUE AT ONE END LOOSELY POSITIONED IN SAID SLOT PROVIDING CLEARANCE BETWEEN THE SIDES OF SAID TONGUE AND SAID SLOT TO ALLOW FOR SLIGHT MISALIGNMENT BETWEEN THE PISTON MEMBER AND THE CONNECTING ROD MEMBER AND HAVING ITS OTHER END SECURED TO SAID RAM. 